(19)
(11) EP 0 297 918 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
25.04.1990 Bulletin 1990/17

(43) Date of publication A2:
04.01.1989 Bulletin 1989/01

(21) Application number: 88306047.7

(22) Date of filing: 01.07.1988
(51) International Patent Classification (IPC)4: H04J 3/06, H04N 7/00
(84) Designated Contracting States:
DE FR GB

(30) Priority: 02.07.1987 GB 8715597

(71) Applicant: National Transcommunications Limited
Winchester, Hampshire SO21 2QA (GB)

(72) Inventors:
  • Gledhill, Jeffrey John
    Eastleigh, Hampshire (GB)
  • Avon, Peter Anthony
    Petersfield, Hampshire GU 31 4NX (GB)

(74) Representative: Crawford, Andrew Birkby et al
A.A. THORNTON & CO. Northumberland House 303-306 High Holborn
London WC1V 7LE
London WC1V 7LE (GB)


(56) References cited: : 
   
       


    (54) Digital synchronisation


    (57) A method and apparatus for detection of a digital synchronisation word, or sequence of words, uses a state machine. The state diagram is implemented in a detector memory with feedback of the memory output through a latch to constitute part of the next memory address. The input data is used bit by bit as another part of the detector memory address. A decoder memory decodes the state information in the detector memory output and produces synchronisation information.
    A particular state diagram for sync acquisition includes feedback paths. A particular state diagram for lock maintenance enables lock to be maintained depending on the number of errors in the successive detected syne words.







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